1. Field of the Invention
The present invention relates to improvements to bypass connections for flexible (i.e. elastic) pipes, reinforced or not, sheathed or not, obtained by molding a coating of junction material, such as rubber, more particularly about a rigid tubular insert, and a process for manufacturing these connections.
2. Description of the Prior Art
Bypass connections obtained by molding a coating of junction material are already known in two different cases:
in the case of a bypass connection between a main pipe and a secondary pipe, itself also flexible, reinforced or not, sheathed or not, in which the junction material is molded about end zones of the main and secondary pipes which overlap mutually, while leaving an access to the pipe-pass orifice, and
in the case of a bypass drain connection, in which the junction material is molded, at least in part, about a threaded or tapped rigid tubular insert intended to receive a plug or a drain screw, respectively, and around the bypass orifice of the main pipe.
In the first case, the mold which provides the outer shape to the coating of junction material is formed by two shells, whereas in the second case the mold is made in one piece.
The mold contains:
a main rigid core for supporting the main pipe, in both cases, and
a rigid secondary core for supporting the secondary pipe, in the first case, or for supporting said threaded or tapped insert intended to receive said plug or said drain screw, in the second case.
Now, positioning and removing the secondary core is a difficult and costly operation, and becomes impracticable in the case of a bypass connection between two main pipes, close and parallel to each other, namely in the case of a "bridging".